Biggest first week of 2012- 374,000
Biggest first week for a Hip Hop album- 253,000
Highest selling album released in 2012- Lionel Richie's Tuskeegee @ 912,000 w/ 199K sold in week 1.
Nas doing 115K-125K isn't bad considering it's on par w/ Usher and Chris Brown's sales who have had at least two charting singles. Chris Brown and Usher also had Top 10 singles. What's important is whether the album consistently sells after. This year has had some historical second week drop offs.
It was far fetched for Nas to do 200K first week in 2012. That's like selling 350-400K first week last year. For whatever reason, this year has had very low debuts even from some of the bigger artists. I can only think of a couple of artists who dropped this year that matched or exceeded the first week of previous releases. Even then, they still experienced huge drop offs.